The objectives of the proposed research is to gain information to explain the gratifying results obtained in the prevention of painful neuroma in four patients treated by a recently developed new technique of nerve fascicle ligation. This technique, as well as variations will be applied to the study of neuroma formation and prevention in both cats and monkeys. Axoplasmic (fast) flow studies with 3H leucine an recording of spontaneous dorsal root potentials produced by neuromas are planned. These investigations will be complemented by light and electron microscopy studies of nerve, ganglion, rootlets and spinal cord. Such histological findings will be compared with those found in non-painful and painful neuromas obtained from patients undergoing reconstructive nerve surgery. Such studies will provide further information on the mechanism of formation and prevention of painful and nonpainful neuromas in man.